DE2148514B2 - Electrically writable flat printing plate - Google Patents

Description

The aim of the invention is an electrically writable cover layer 14 contains a whitish color

Planographic printing plate in which the binder of the cover material is 65 with a film-forming binder, so that the layer of zinc oxide in such a particle size and quantity above-described covering function is fulfilled. Of the is added so that an optimal top layer is achieved. chosen so that it is sufficiently conductive and the passage

3 ⁴

Electrical Power Flow for Recording The following is an example for the present purpose In addition, the dye particle detection is shown: size and the dye load carefully regulated, so example that the cover layer 14 quickly in a water-

can transform the attractive and holding state 5 A sheet of paper 25 x 37.5 cm

and thereby the use of the plate as piano-coated: A conductive ^Bes

graphic form. from the following substances in Ge

The dye preferably consists of zinc oxide, parts of printing ink

However, any dye or any combination of polyvinyl chloride parts can be used

from dyes are used, which the geeig- io Dioctylphthalat ^ Tei

has suitable properties for such use. Methyl ethyl ketone ** ° parts

The zinc oxide should have such a conductivity,

that the resistance was not greater than 10 * ohms / cm polyvinyl chloride ^

measure in pressed powder compacts between the mixed in and the printing ink

is medium electrodes. This resistance is based on 15 dioctyl phthalate added uieooigc ^

commercially available recording devices, but settling was stirred until the mass cm

a zinc oxide with a higher resistance was used and had a thick consistency

Particle size is an important consideration, 20 and a layer with

and it has been found that a particle about 0.0075 mm ^ ^^} ^ \ ^^ 0.5 × 10 ^-3 mm reacts with the stain too slow to stand of about 200 ^{ohms /} ™ / "" S ™ _{(in Ge} _ to make the surface of the layer hydrophilic. A second coating compound was then (in Oe

In addition, larger particles react as follows.

constantly, and there is a tone during the 25 Acrylpolymer ^ ^ ^e ! ^e

pianographic process. The smaller the particle printing ink or soot 2 parts

size is, the faster and more complete is the Tolusol ^ ^ ^e !

Reaction. Zinc oxide with a particle size of ethyl acetate ^{5 Τ} ΐ ·,

0.2 x 10 ^-3 mm has excellent properties, and wax

it is believed that smaller particle sizes of 30. ,,. , _a soft one

are of greater advantage. These parts were mixed and mixed up to a white

The amount of pigment in the top layer 14 is stirred to consistency. Wire rod up

controlled, since commercially available The second mass ^^ "^^ Äragen

Resins in general are hydrophobic, and therefore a thickness of about * WJ ™™ & £ Sta must the dye in an amount sufficient to be 35 wherein the Oberflachenw.derstand to approximately to the reluctance of the binder compared to 400 Ohm cm increased. wfawcren layers

Overcome water. In general, the top, top side can be used to create conductive layers

With a dye-to-binder ratio of 5 parts, a topcoat was prepared as follows. Dye to 1 part binder and 25 parts dye zinc oxide (10 ³ Ohm / cm more specific

1 part of binding agent, which is 40 resistance) ^{1S Te} l! ^e

weight shares. Preferably the coloring methanol should be ¹⁵ T ?! ..

material to binder ratio in a size range tricresyl phosphate °> 1 ^Te "

from 12 to 20 parts dye to 1 part binder polyvinyl acetate ^{1 part}

Sit ^{1 Fbtff id di Shiht fl0Ckig} 45 The above-mentioned components were in a

^ dikrii ^ pumw ^ «^ and ^

After the recording on the disk, it is given a high level of digitization

a stain that wets the zinc oxide into a hydro- a wire rod b.s to a thickness of about

converts phile connection. Applied at a typical 0.005mm.

Reaction reacts with the zinc potassium ferrocyanide These so ^v ° ^rbereitet% ^ ™ ^

oxide and produces zinc ferrocyanide as follows: ₅ o ^ Ä Z

2ZnO - K FFe (CN) 1 + 4H- marked surface with a 1 percent marked

2ZnO K ₄ [He (CNy f ⁴ ", _{mo f 4K + acidified solution of} potassium ferrocyanide wetted. The

^{21 ( ) eJ} ' ² plate was then immediately after a conversion

The above conversion of zinc oxide into a hy- 55 lunj to a conventional jj ^ g ^ jgj;

drophile connection is for illustrative purposes only. set. Four thousand copies were made without

Any reaction that produces that of the subsurface can be used. _ς . _{ρ] 1ρπι}

Converts zinc oxide into a hydrophilic compound. One like above ^^^ ™ ^ ™

The above reaction can be achieved by wetting the open press without treatment; m t a y

Drew plate with a 1% aqueous solution 60 solution applied. The copies were perfect

of potassium ferrocyanide. flaky.

1 sheet of drawings

Claims (1)

1 2 According to the invention this is achieved by Claim: that the zinc oxide has a particle size of at most 0.0005 mm, to the binding agent in one piece Electrically writable planographic printing plate with a weight ratio of 12 to 20 parts of zinc oxide from a conductive paper base sheet, which is 5 1 part binder and by a hydrophilicity overlying, can be rendered hydrophilic by a conductive agent using carbon powder. So that will made hydrophobic and oleophilic agents - maximum single copy reproduction achieved without layer and one exposing the center that an end coating is required to cover the plate layer makes electrically writable cover layer made of water-receptive. Zinc oxide consists in a binding agent, the invention is characterized in the following in connection with that the zinc oxide of the drawing shows a particle size of at most 0.0005 mm on the basis of an exemplary embodiment. The figure shows a section through a plate produced according to the present invention in a weight ratio to the binder with nis from 12 to 20 parts of zinc oxide to 1 part. Binding is a schematic representation of the recording medium and by a hydrophilizing _{agent 15} process. can be made hydrophilic. In the drawing, a pad 10 is shown, made of paper, cardboard, metal foil or another, corresponding material exists. The surface of the base 10 is covered with an ao dark-colored coating 12 or a dark-colored The invention relates to an electrically colored layer 12, which is an electrically conductive writable Planographic printing plate, which is made of a conductive material, such as carbon or ge-paper base sheet, an overlying metal, powdered by carbon, in a binding powder that forms a film contains made conductive, hydrophobic and oleophobic agents. For a typical approach to that The phile middle layer and a conductive layer 12, which is dark colored, exposing the 25, is applied to the Middle layer electrically writable top layer U.S. Patent 2,664,043 pointed out which consists of zinc oxide in a binder. typical approaches with the only change in that So far, plates or sheets are represented by using the approach of the present invention, which a writing system carrying an electrical voltage is that the approaches are modified so that Stick and by burning away the top layer to expose it wax, silicone or some good water repellent an underlying agent that is condensed in the color contains a sufficient amount to prevent the tracing layer has been recorded (USA.- Layer 12 to make it hydrophobic, and in one not Patent 2,983,220). Such plates or sheets are in excessive amount to the coating so manufactured so that, as a pianographic print, it does not prevent it from being anchored. The layer For example, the plate used on a piano printing press should use wax on a dry fixed can be. To achieve this, the fabric component base will contain between 0.05 and 6%. the A plate of a washing solution, typically ferric chloride, dark colored, conductive layer 12 may have one or or subjected to aluminum chloride in water so as to contain two layers. a hydrophobic layer on the surface of the layer 12 is a cover described in more detail Reflects plate. 40 layer 14 applied, which is white or in color The application of a washing solution does not end with layer 12, so that layer 14 is applied wishes, as this firstly discolors the plate and then the area under a recording pen impaired by the visible contrast, secondly, the dark appearance of the underneath is removed Interfering with recording, since the additional lying layer 12 by the very small area of the Layer the desired electrical properties 45 layer 14 shows through, which either completely and thirdly, because the washing solution is in or partially removed or by the electrical impactor extremely thin layer must be applied, the driven pen 16 is dissolved. The spelling Disturbances in the recording on a minimum pin 16 can result from an electrical supply or signal measure to reduce the layer not continuously and source 18 are fed. thus the pianographic properties of the 50 If a large number of copies of the on the upper layer often inadequate. Record formed records is desired, The use of zinc oxide-containing binding agent is used to wet the plate with a stain, which continues middle layers is described as a top layer of electrically down to the dye in the top writable Planographic printing plates are known per se layer 14 umzuwan- (German Auslegeschrift 1 014 128). 55 your, so that the surface of the layer 14 water It is also known that a lithographic plate can pull and hold. After the conversion (German Auslegeschrift 1 210 437), in which the plate can be used as a pianographic printing form dry film from the smallest, separated from each other can be used without further treatment. In the Zinc oxide particles; From this it can be seen that the intermediate layer 12 lies on the recording surfaces that zinc oxide with a particle size over 0.0005 mm 60 free, which is hydrophobic and oleophilic, so that the with the applied solution or stain, the dampening solution is repelled too slowly and the printing ink continues to react, it is only stated in a very general way that the pianographic process is included that these particles must be very small. will.